Answer:
x = 60°
Step-by-step explanation:
[tex] \cos \: (2x + 60) = - 1 \\ \cos \: (2x + 60) = \cos \: 180 \degree \\ 2x + 60 = 180 \degree \\ 2x = 180 \degree - 60 \degree \\ 2x = 120 \\ x = \frac{120}{2} \\ \huge \red{ \boxed{ x = 60 \degree}}[/tex]